The present disclosure relates to a pump, pump assembly, or pump system, and an associated method of manufacturing same. It finds particular application in conjunction with a vane pump, however, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications that encounter similar problems or require similar solutions.
In an exemplary vane pump, a pressure plate and port plate are two separate concentric components axially clamped and/or bolted together, for example, at several circumferentially spaced locations. The port plate is preferably constructed of tungsten carbide or a material with similar properties. The pressure plate is preferably constructed of aluminum alloy or a material with similar properties. Use of a lighter weight pressure plate constructed from aluminum alloy or similar material contributes to significant weight savings which is well known in the art.
The two port plates are axially spaced apart and define the pumping chamber therebetween, and also receive the cam ring, rotor, and vanes. Tungsten carbide is used due its wear resistance properties to minimize wear and tear from the movement of the rotor and vanes.
The interface of each of the pressure plates and associated port plates acts as a seal to limit the exposure of the high-pressure oil film trying to seep between the plates. To ensure effective sealing between the pressure plate and the port plate, it is paramount to provide a high degree of “flatness” to the port plate. Any compromise on the degree of flatness can lead to ineffective sealing and thereby cause more oil seeping in, which further causes pressure build-up between the interface of the pressure plate and the port plate leading to undesired deflection of the port plate. The deflection may cause the port plate to rub against the rotor and vanes which is undesirable and could lead to premature pump failure.
Consequently using a separate port plate and a separate pressure plate requires, for example,                a finer degree of flatness for an effective seal between the port plate and mating pressure plate thus leading to higher machining costs;        tighter deflection control of the port plate due to limit oil seeping in at the interface of the port plate and pressure plate potentially leading to rubbing against the rotor and vanes;        use of a heavier port plate of tungsten carbide or a material with similar properties leads to higher overall pump weight and cost of machining the port plate; and        lower reliability of the pump and potential premature pump failure due to one or more of the above reasons.        
This disclosure remedies one or more of these problems in a simple, reliable, effective, and inexpensive manner.